Field of the Invention
The invention relates to transport apparatus particularly for transporting signatures from a continuously moving saddle chain of a saddle binding machine to a working station.
For the production of bound printed products, such as books, periodicals, magazines, and so forth, transport and gathering devices are well known. After collating single sheets or signatures on a gathering device, the collated bundles have to be fed by a transport device to further processing stations such as a trimming or stitching station.
A known transport device for feeding a bundle of collated signatures, a so-called book, to a further working station uses a shuttle assembly to move the bundle of signatures to a stitching station. The shuttle assembly grips the bundle and moves it to the stitching station where it is released. Then, the shuttle mechanism returns to grip the next succeeding bundle of signatures. When the shuttle mechanism engages the next bundle, it also engages the previously moved bundle of signatures located at the stitching station and moves the signatures, which in the meantime have been stitched, to a delivery station, while the next bundle is moved to the stitching station. A transfer device and a stitching machine of this general construction is known from U.S. Pat. No. 3,317,026. The existing systems used on many saddle stitchers use a so-called reciprocating gripper system. It comprises a row of grippers which, when closed, press against the outside of the book. These grippers are connected to a xe2x80x9cbackupxe2x80x9d bar on the inside of the book, so that one half of the book is trapped between the grippers and this xe2x80x9cbackupxe2x80x9d bar. The grippers open, in order to release the book at the stitching station and move back in their open condition. The grippers close on the continuously moving book on the saddle chain when they start to move forward again. In this way, they accelerate the books away from the conveyer chain and stop them at the stitching position. The whole gripper and backup assembly is supported on a linear slide and driven backward and forward by a crank mechanism.
This system, however, comprises a relatively large reciprocating mass which requires heavy support frames and a lubricated slide system. When the assembly is driven from a crank, velocities cannot easily be optimized due to the fact that a crank is only capable of simple harmonic motions. Finally, as the gripper and backup bar assembly can only contact the inner half of the book, the higher speed outside of the book is uncontrolled and this tends to cause the spine of the book to move off the saddle apex during quick. deceleration resulting in off-center stitching.
It is therefore an object of the invention to provide a new and improved method of transporting and transport apparatus, especially for transporting signatures, from a continuously moving chain to a working station.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, an apparatus for transporting a bundle of signatures moving continuously on a saddle chain to a working station, comprising an indexing chain moving with variable speed, and a clamping unit for keeping the bundle of signatures at a predetermined position on the indexing chain.
In accordance with another feature of the invention, the indexing chain succeeds the saddle chain.
In accordance with a further feature of the invention, the clamping unit for keeping the bundle of signatures at a predetermined position includes a gripper element mounted on the indexing chain.
In accordance with an added feature of the invention, the apparatus includes a linear cam.
In accordance with an additional feature of the invention, the cam is operatively engageable with the gripper elements for opening and closing the gripper elements.
In accordance with yet another feature of the invention, the clamping unit for keeping the signatures at a predetermined position includes a belt for keeping the bundle of signatures in close contact with the indexing chain, the belt being disposed to at least one side of the indexing chain.
In accordance with yet a further feature of the invention, the clamping unit for keeping the bundle of signatures at a predetermined position includes rollers for keeping the signatures in close contact with the indexing chain at least on one side of the indexing chain.
In accordance with yet an added feature of the invention, the clamping unit for keeping the bundle of signatures at a predetermined position includes at least one blowing device for blowing air to the bundle of signatures moving on the indexing chain, the at least one blowing device being located on at least one side of the indexing chain.
In accordance with yet an additional feature of the invention, the blowing device includes a nozzle.
In accordance with still another feature of the invention, the clamping unit for keeping the bundle of signatures at predetermined positions comprises feeder pins.
In accordance with another aspect of the invention, there is provided a method for transporting a bundle of signatures moving continuously on a saddle chain to a working station, which comprises the steps of feeding a bundle of signatures with continuous speed to a transfer point, transferring the bundle of signatures from the continuously moving saddle chain to an indexing chain moving with variable speed, acting upon the bundle of signatures in order to keep the bundle of signatures in a definite position on the indexing chain, and moving the bundle of signatures on the indexing chain with a variable velocity profile to the working station.
In accordance with a further mode, the method of the invention includes the step of acting upon the bundle of signatures by a clamping unit for keeping the bundle of signatures at a predetermined position whereat the clamping unit moves with substantially the same velocity profile as the indexing chain.
In accordance with an added mode, the method includes performing the step of acting upon the bundle of signatures by a clamping unit blowing air onto the bundle of signatures, the clamping unit being disposed in a stationary manner at a side of the indexing chain.
In accordance with an additional mode, the method of the invention includes, during the transfer of the bundle of signatures from the saddle chain to the indexing chain, maintaining the velocity of the indexing chain substantially the same as the velocity of the saddle chain.
In accordance with a concomitant aspect of the invention, there is provided a saddle binding machine having a signature conveyor for conveying and gathering a plurality of signatures, comprising a transport apparatus having at least one of the foregoing features.
The invention of the instant application is thus especially directed to transport apparatus for transporting a bundle of moving signatures from a first moving chain, a so-called saddle chain, to a working station. When a number of gathered signatures, hanging upon one another on the continuously driven saddle chain, reach the point at which this bundle of signatures is to be transferred to the working station, the transport apparatus transports this bundle from the continuously driven saddle chain to the working station. This transport apparatus succeeds the saddle chain and is driven independently from the saddle chain. It comprises a second moving chain, a so-called indexing chain, which is driven with a velocity profile having variable speed. Furthermore, the transport apparatus according to the invention preferably comprises a devikce for keeping the bundle of signatures at predetermined positions on the indexing chain. At the time of the transfer of a bundle of signatures from the continuously moving first chain, namely a saddle chain, to the second chain, namely an indexing chain, that has a velocity profile, the second or indexing chain moves with the same speed as the first or saddle chain. Just after the back or trailing edge of the bundle of signatures has passed the transfer point, a device for keeping the bundles of signatures at registered positions on the indexing chain acts upon the bundle of signatures and keeps acting thereon at least as long as the working step lasts. After that, the indexing chain speeds up according to a predetermined velocity profile, accelerates the bundle of signatures away from the continuously moving saddle chain and brings the bundle of signatures to a working station, e. g. a stitching station. Before the bundle reaches the working station, the indexing chain is decelerated and stops at a position whereat the further working step, e. g. stitching, is to be performed. After this working process has been finished, the indexing chain accelerates again and moves the bundle of signatures to a second working station or to a transfer position where the bundle of signatures is transferred to a final working station or to another transport device. During this whole procedure, the device for keeping the bundle of signatures at a predetermined position on the indexing chain acts upon the bundles of signatures. This keeps the bundles of signatures at registered positions on the indexing chain during the whole feeding and working process.
Combining a continuously moving first or saddle chain, on which the bundle is collated, with a second or indexing chain having a variable velocity profile and being arranged so as to succeed to the first continuously moving chain, makes it possible to accelerate the bundle of signatures away from the first continuously moving chain. Thereby, the velocity profile of the second chain can easily be adjusted to the required demands by driving and control equipment coupled to the second chain. The driving and control equipment drive the second chain and control the velocity profile thereof. The device for holding the bundle of signatures at a predetermined position on the second chain ensures a fixed and definite position of the bundles on the moving indexing chain during its movement, as well as during the working process at the working station. As a consequence, this allows high speed and high acceleration of the indexing chain, as well as high speed working at the working station.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a transport apparatus, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.